The present invention relates generally to a lid for open top containers in a vacuum system for facilitating the removal of solids and liquids from an air stream. More particularly, the invention relates to a lid which is adaptable to open-top containers, minimizes liquid carryover out of the container, and enables liquid level control.
In the area of environmental clean up, vacuum systems are frequently used to recover liquids, sludge and dry products. In such cases it is useful to remove these recovered particles or liquid from the stream of air prior to the stream entering the main vacuum system. Conventional systems comprise a vacuum generating device, a suction source line extending between the vacuum generating device and an outlet port on an intermediate collection receptacle, and suction wand connected to an inlet port to the receptacle.
Intermediate collection receptacles are often utilized in situations where one does not want hazardous materials carried though to a main vacuum source. Receptacles such as drums and canisters are inexpensive, readily available and can hold a large amount of particulates and liquid. Furthermore, once a drum or canister is full it can be transported to a disposal or storage site, should this be required.
As is typically the case with accidental spills, the liquid can be hazardous including having flammable characteristics. Vacuuming can volatilize or atomize the liquid which can accentuate the hazard if entrained in the discharged flow and carryover beyond the collection container.
In U.S. Pat. No. 5,525,396 to Rudolph et al. a particle collector lid is described. This lid is adapted to close off the upper end of a container and provides inlet and outlet chambers shaped so as to direct air entering the container to flow in a curved and downwardly inclined direction. This directing of air establishes a cyclonic action in the container which results in separating out larger particles, such as wood chips, from the air stream. However, the device disclosed by Rudolph et al. does not work well when extracting liquids from a stream of air for a number of reasons. First, the cyclonic action does not encourage knock-out of liquid from the air stream and some entrained liquid will exit through the outlet chamber and into the main vacuum system. Second, once the container is full, any additional liquid overflows into the outlet chamber and is likewise sucked into the main vacuum system.
A transparent lid, as taught by U.S. Pat. No. 6,210,457 to Siemers, allows an operator to visually inspect the amount of particles or liquid collected in a container. However, such a device still requires continuous observation of the growing amount of liquid inside and risks liquid overflowing into the main vacuum system if left unobserved. This device also does not address the liquid entrainment problem.
One device that prevents an overflow of liquid into the main vacuum system is the Drumlt(trademark) device manufactured by Elastec Inc. of Carmi, Ill. The Drumlt(trademark) lid includes a two-ball valve at the container exit to shut off the air flow when the drum is full of liquid. However, from experience the applicant has found that interaction of the two balls can result in an improper seal. Furthermore, applicant has found this system to have a high entrained liquid carryover. Applicant hypothesizes that stream of air and liquid is directed against the bottom of the container (or top any collected liquid) which results in some of the liquid remaining entrained in the stream of air or being re entrained. The two-ball valve is insensitive to increased liquid carryover, activates only upon high liquid contact and is slow to respond. These deficiencies limit the Drumlt(trademark) device""s ability to remove liquid from the stream of air resulting in passage of a higher than desirable amount of liquid to the vacuum generating device.
In U.S. Pat. No. 5,970,573 to Lahaye, spray and incoming mist is discharged from a nozzle at an inlet port and is directed downwardly to the bottom of the container, deliberately away and separated from the outlet port and vacuum blower by a depending weir or direction plate. Lahaye has attempted to address the entrainment problem to some extent, however, like the Drumlt(trademark) device, liquid entrainment can still result and the direction plate extends deeply into the container affecting its fill capacity.
Accordingly, there is still a need for an apparatus and method for adapting to easily procured receptacles such as drums, that limit liquid entrainment in a stream of air, and that provide reliable shut off in high liquid situations. Additionally a need exists, beyond the prior art, for a device or method to control accumulations of liquid so as to maximize vacuuming operation.
In one aspect of the present invention, a universal drum lid for vacuum systems is provided for fitting to open top receptacles and maximizing liquid knockout, minimizing liquid entrainment resulting in liquid carryover from the receptacle.
In another aspect of the invention, a lid is provided for superior liquid collection management while retaining the ability to maximize liquid knockout and minimize liquid carryover from the receptacle.
In one embodiment of the invention, an inlet port is configured to intercept downwardly flowing influent with a baffle and redirect the flow perpendicularly or laterally against an adjacent side wall of the receptacle which is opposing or away from the ultimate exit. Through the addition of a preferred disengagement chamber above the baffle, influent velocity is reduced for disengaging suspended particles, including liquid, and permitting debris to pass the baffle without blockage. Preferably the baffle is suspended below the lid and in the path of the influent by a blocking plate which isolates the inlet port from the outlet port. For minimizing liquid carryover out of the outlet port, preferably the outlet port comprises a single float ball-valve which is configured to close the outlet port even prior to the float ball contacting a collected high liquid level surface.
In another aspect of the invention, a drum lid is provided which includes a combination of elements which enable substantially continuous management of liquid collection and removal. The preferred lid includes a downcorner conduit which is adapted for connection to a liquid removal device such as a suction pump. Such a system draws any collected liquid from a location sufficiently below the outlet port so that the float ball is not actuated and the characteristics of the flow steam approaching the outlet port do not actuate the ball valve. In the case of a conventional drum, it is advantageous to extend the conduit to the bottom of the drum.
Accordingly, in a broad aspect of the invention, a planer lid is provided comprising an inlet port fit into and located adjacent a periphery of the lid and oriented for receiving the mixed stream and redirecting it downwardly into the container adjacent a vertical side wall; a baffle spaced from and positioned below the inlet port so as to intercept the mixed stream and redirect the stream laterally; a plate depending from the lid adjacent the inlet port and extending downwardly to the baffle for blocking at least a portion of the laterally redirected stream so that substantially all of the laterally redirected stream is towards the side wall for removing a substantive amount of liquid from the mixed stream; and an outlet port fit into the lid and adapted for connection to a vacuum source, the outlet port spaced from the inlet port and plate for discharge of the gas stream.
Preferably, the lid comprises a chamber to which the inlet port is connected, the chamber having greater lateral dimensions than the inlet port and the baffle. More preferably, the chamber is raised above the planer lid so as to enable closer spacing of the baffle to the lid.
In another aspect, a conduit is also depending from the lid to a suction end for engaging collected liquid and when adapted to a pump, liquid can be withdrawn on a substantially continuous basis.